Greases



ew-r d x UNITED STATE causes Hubert J. Liehe, Hammond, lnd., assignor to'Standard Oil Company,

ration of Indiana Chicago, 111., a corpo-bv No Drawing. Application May29, 1942,

lSerial No. 445,076

1': Claims. (cl. ass-33.2)

The present invention relates to improvements in greases and moreparticularly to relatively low soap-content greases of the type of ballbearing greases, mine loader greases and other anti-friction bearinggreasesand to the method of preparing the same. l I

An object of the invention is to provide ,a relatively low soap-contentgrease of the type of ball bearing grease, mine loader grease, etc.,which further object of the invention isto provide a grease of the typeof ball bearing grease which is stable against oxidation. Other objectsand advantages of the invention wfll become apparent from the followingdescription .thereof.

I have discovered that the foregoing objects can be attained byincorporating in relatively low soap-content greases, of the type ofball bearing greases and similar anti-friction bearing greases,relatively small amounts of sulfonic soaps, preferably the soaps ofpreferentially oil-soluble sulfonic acids obtained in the treatment ofmineral oils with strong I sulfuric acid. Greases of the type hereinreferred to contain from about 2% to about 25% of an-alkali metal soapor mixhn-es of alkali metal soaps and an alkaline earth soap of fattymaterials such as fats or fatty acids.

Thus, the grease may be prepared, for example. with sodium, potassium orlithium soaps of fats or fatty acids, preferably the sodium soap, ormixtures of such soaps and an alkaline earth soap, such as for examplesoda-lime soaps. Fats or fatty acids such as tallow, Standard FattyAcids, stearic acid, animal fatty acids and the like are suitablematerials from which to prep re the aforementioned soaps, although Iprefer to employ saturated fatty acids such as stearlc acid.

In order to obtain the above-mentioned objects it is essential 'toincorporate in the grease a small amount namely from about 0.25% toabout 5% of a suli'onic acid soap. The sulfonic acid soaps which areparticularly well adapted for this particular grease are the'soaps ofpreferentially-oilsoluble sulfonic acidsobtained-in the process oftreating petroleum oils, particularlyviscouspetro-x leum oil stocks.with concentratedv or fuming sulfuric acid. In the treatment ofpetroleum oils with concentrated or fuming sulfuric acid -there are.obtained two layers, an acid sludge layer containingpreferentiallywater-soluble sulfonic acids which because of theircharacteristlc greenish color are'known in the art as v green acids, andan upper oil layer which contains the preferentially oil-soluble sulfonicacids which have a reddish brown co'lor and arereferred to in thepetroleum refining art as mahogany acids. After the acid sludge isremoved the acid treated oil layer is then treated with a neutralizingagent v such as an alkali metal hydroxide, for example sodium hydroxideor potassium hydroxide, preferably the former, whereby the sulfonicacids in said oil layer are converted to the corresponding soaps whichare then separated from the oil by means of suitable solvents such asfor example alcohol. Alkaline earth soaps such as for example calcium,barium, magnesium soaps and the heavy metal soaps of these sulfonicacids can be obtained by reacting the mahogany acids with an hydroxideor oxide of the desired alkaline earth metal. The metal soap can also beobv tained by double decomposition using alkali metal soap and analkaline earth salt.

While the scans of preferentially oil-soluble sulfonic acids derivedfrom treatment of viscous petroleum oils with fuming sulfuric acid canbe suitably employed, I have obtained especially good results byemploying the soaps of preferentially oil-soluble sulfonic acids derivedfrom a particular sulfuric acid treatment of petroleum oil distillates,namely the soaps of the preferentially oil-soluble sulfonic acidsderived by treating petroleum distillates of from about '10 seconds toabout 500 seconds or higher and preferably from about 200 seconds toabout 400 seconds Saybolt ,Universal at 100 F. with from about 6 poundsto about 9 pounds andpreferably from about '1 pounds to about 8 poundsof concentrated sulfuric acid,-particularlyf1nning sulfuric acid pergallon of oil.

The method of obtaining these desirable soaps of preferentiallyoil-soluble sulfonic acids derived frompetrolemn oils is illustrated bythe following example:

The petroleum oil distillate drawn, the next one-half poimd of fumingsulhaving Saybolt' Universal viscosity'at I". of from about 200 2.iuricacidisaddedtotheoil. Thetemperature oftheoil beforethefumingacidisadded thereto ing oil-soluble sull'onic acids dissolved therein, is

neutralized with a solution of sodium hydroxide. The aqueous alkalisolution is then separated from the oil solution containing dissolvedtherein sodium soap of sulfonic acids and the latter then separated fromthe oil by extraction with alcohol of about 60% strength. The alcohollayer contalning dissolved sodium sulfonates is then separated from theoil and subsequently distilled to recover the alcohol'and water. Thesulionic soap obtained in this manner contains from about 30% to about60% sodium sulionate, from about 30% to about 60% oil, from about 1% toabout water, and up to 10% of inorganic salts which may be removed b theprocedure hereinafter described.

'lhe above procedure may be modified after the acid sludge is removedfrom the acid treated oil. The oil containing dissolved sulfonie acidsis extracted with about 60% alcohol to remove the sulfonic acids whichmay then be neutralized with sodium hydroxide and subsequently freed ofthe alcohol by distillation.

The crude soaps of these preferentially oilsoluble suli'onic acidsobtained by the procedure described above may be freed of inorganicsalts by purification. This purification is preferably parts of 50%orhigher strength alcohol, preferably alcoliol of 60 to '70% strength,and allowing the salts to settle while maintaining the mixture withinthe temperature range of 130 to 175 F., preferably 155 to 165 F. Whenthe salts have settled the supernatant alcohol-soap layer is separatedand the alcohol is recovered by conventional distillation procedure. Thecrude soaps can also be purified by extraction with mixtures ot'apetroleum solvent such as naphtha and alcohol of from about 10% to about45%, preferably 40% concentration. f

Sulionates can also be obtained by treating petroleum oils with $03,SOzCla, or with a mixture of gaseous SO: andClz.

Greases of the present invention are suitably Pounds Single pressedstearic acid 3.1 Soda mahogany soap 0.9 Dry caustic soda.-. 0.52 SAE 50oil a 16.3 SAE 10 oil stock. 79.5 The finished grease had the followingcomposition:

Per cent Soda soap of stearic acid. 3.3 Soda mahogany soap (oil-freebasis) .4 Mineral nil 96.

Example II A ball bearing grease having the following for-- mula:

Pounds Single pressedstearic acid 13.6 Soda mahogany soap 4.0 Drycaustic soda. 2.25 I SAE 50 oi 13.8 SAE 10 oil stock 67.5

' This grease which has the following composition: Per cent Soda soapoi. stearic'-acid---.' 14.6 Soda mahogany soap (oil-free basis) 1.6 Oil.83.8

aeoavao is d. Thus, whllei prefer to use a mineral oil having aviscosity of about 300 seconds Saybolt Universal at E, mineral oils of60 secgreases made in accordance with the present invention.

Example I A soft smooth mine loader grease was prepared having thefollowing formula:

has a low penetration difi'erential, a smooth struc- Penetration at w r.Dm 'r. c. c. m Grease Structure gg Doing 1 Unwol'ked Worked o 77 200 250No. 1 Smooth- 261 280 19 382 can 400 zoo zoo 240 N0. 2. Shortflbl'fl.-.-.. 151 283 132 363 700 580 400 204 No.3. ..do........;.. as334 121 an 500 388 290 we I Torsion Toohud those coming within thefollowing general formula:

The choice of oil used will be largely determined by the nature of theservice for which the grease cone consistometer test descrfced in the ona Gas Journal, :1. 40 (March so. ma). p e as.

The above data show that greases of the present invention are superiorto conventional antifriction greases inthat the former have a smootherstructure, have lower diiferentials between the unworked and workedpenetration.

have higher drop points, and flatter temperatureconsistency curves. I

, Example Ill, A- mixed soda-lime soap grease having a com position of aa Per cent Soda-lime stearic acid soap 11.2 Soda mahogany soap (oil-freebasis) 1.4 Oil 87.4

was prepared from the following-formula:

- Pounds Single pressed stearic acid 10.4 Hydrated lime 0.2 Dry causticsoda 1.6 Soda mahogany soap 3.4 SAE 50 nil v 16.60 SAE 10 oil stock69.60

The soda mahogany soap in the above formu las was 40% soda mahogany soapand 60% oil. The greases of Examples II and III before filling werestirred cold in the mixer to give a very smooth grease without anysubstantial loss in consistency. The low soap content grease of ExampleI was filled hot without workinpin the mixer.

-In preparing greases of the hereindescribed type the desired amount offatty material'and the sulfonic soap are charged to the grease mixer andsumcient oil added to make a base containing from about 40% to about 50%oil and from about 50% to about 60% soap. The mix is then heated to225-2'35 F. and a saponifying agent, for example caustic soda, in a 48Baum solution, is then gradually added in an amount sufficient to reactwith all of the fatty material and leave approximately 1% excess causticin the base. The temperature is maintained at about 225 F. to 240 F.until the base becomes heavy, and the temperature then graduallyincreased to about 280 F. to 300 F. and maintained at this temperatureuntil the base becomes very short, heavy and plastic; Heating of the mixis then stopped and additional 011 graded in the mixture while thetemperature drops to about 250 E,

which temperature is maintained during the remainder of the grading-instep. When the grease has been adjusted to the desired consistencyheating is discontinued and water introduced into the kettle Jacket tocool the mixture as rapidly aspossible, and stirring continued until themix ture becomes smooth and of the desired texture. In the case of mixedsoap greases such as soda lime soap grease, thelime, for example, isadded inthe early stages and allowed to react with the of the mixture isgradually lowered from 250 1"."

to about 160 F. while the oil is being graded in.

If desired the sulfonic acid soap can be formed insitu by using sulfonicacid and neutralizing in the mixer simultaneously with the preparationof the fatty soap base.

Greases'made in accordance with the present invention may. have added tothem small amounts, namely from about 0.01% to about 2.0% of variousaddition agents to impart there to certain desired properties. Forexample the grease may contain a pour point depressor, oxidationinhibitor, oillness agent and/or other. types of additives. Oxidationinhibitors especial-,- I 1y well adapted for use in the hereindescrlbedgreases are polyamines, such as triethylene 'te't ramine, ,and theneutralized reaction products or"; as lass-mu; tel:

I erably an olefinpolymexgparticularly a mono.

olefin polymer havinga molecular weight within the range of from about150 to about 50,000 or 10,000, such as isobutylene polymer. I

The phosphorus sulfide-olefin polymer reaction product may be obtainedby reacting a phos- 'phorus sulfide such as P253, P235, P457, P433,etc.; preferably Pass, with an olefin polymer of the type hereindescribed at a temperature of from .about 200 F. to about 500 F., andpreferably from about 200 F. to about 400 F. It is advantagous tomaintain a non-oxidizing atmosphere, such as, for example, an atmosphereof nitrogen, above the reaction mixture. From about 1%to about 50%, andpreferably'from about 5% to olefin polymer reaction product is thenneutralan oxide,.or a carbonate of an-alkali or of an alkaline earthmetal or with ammonia, and preferably with potassium hydroxide. Thisneutralization may be carried out by contracting the phosphorussulfide-polymer reaction product,

either as such or dissolved in a suitable solvent, such as naphtha, witha solution of the neutralizing agent, for example, potassium hydroxidedissolved in alcohol. The neutralization may also be accomplished byadding the dry neutralizing agent, such as KOH, NaOH, NazCOa. IKHCOa,CaO, or dry ammonia to the phosphorus sulfide-polymer reaction product,preferably at an elevated temperature of from about 100 F. to about 400F., preferably in a non-oxidizing atmosphere.

i The neutralized product, as aforesaid, may be, further treated with asalt of a heavy metal to obtain a heavy metal derivative thereof.

The effectiveness of the above additive in grease is demonstrated by thefollowing data obtained in the'Norma-Hofi'man Bomb Test, which 5 isdescribed in Product Engineering for June,

1936. The tests were made with 20 gram sampics at 210 F. for hours withan initial pressure of pounds.

' Increase Sample Soap Additive figgf'fgi g ggg 1 sample .1 Percent Nasteemte Nona... 7.2 7 1,-8' N ne... a1 1.0

0.5 "1.4 foxs" Y Na steorste; 70 "1"'r"" Nasulfonaten; 7

I Additive used was a neutrslized'reactlon, product of phosphorus,

pentasulilde and an isobutyle'ne polymer. 7

1s darker and heavier thsnthe original test sample .more and preferablyfrom about 500 to about I phorus sulfide that will completely react withfiltering or by diluting witha solvent such as ized with a suitablealkali such as a hydroxide.

" At the completion of the tests sanitie'sogi was I slightly heavier anddarker than the original and Samples 4 and 5 showed substantially nochange. Although the invention has been described in connection withcertain specific examples and embodiments thereof, it is to beunderstood that these are by way of example and not by wayof'limitation, and the invention is not to be limited thereby exceptinsofar as defined by the scope of th appended claims.

I claim:

1. A low soap-content grease of the type suitable for ball bearinggrease comprising from about 2% toabout 25% of a soap selected from theclass consisting of an alkali metal soap of a saturated fatty materialand an alkali metal-alkaline earth 10. A stablegrease as described inclaim a in which the oxidation inhibitor is the neutralized reactionproduct of a phosphorus sulfide and a hy- I butylene polymer.

mixed soap of a saturated fatty material, a major portion of which isthe alkali metal soap, awmall amount, not greater than about 5%,sufilcient to produce a smooth consistency-stable grease, ofan oilsoluble soap of a sulphonic acid of the type derived from petroleumoils, and mineral oil.

2. A soft, smooth, low soap-content grease of ing from about 2% to about25% of an alkali metal soap of a saturated fatty material, from' about.25% to about 5% of a preferentially oil- I fatty material, from about.25% to about 5% of an alkali metal soap of sulfonic acid of the typederived from petroleum oils and mineral oil.

4. A grease as described in claim 3 in which the alkali metal soap ofthe fatty material is the soda soap and the alkali metal soap ofsulfonic acid is the soda soap of sulfonic acid.

5. A low soap-content grease of the type suitable for ball bearinggrease comprising from about 2% to about 25% of an alkali metal soap ofa saturated fatty material, from about 0.25% to about 5.0% of aperferentially oil-soluble alkaline earth soap of a petroleum sulfonicacid and mineral oil.

6. A low soapcontent grease of the type suitable' for ball bearinggreases comprising from about 2 to about 25% of an alkali metal-alkalineearth mixed soap of saturated fatty material, a major proportion ofwhich is the alkali metal soap, a

1 ,small amount, not greater than-about 5%, sufii- "-c'ient to produce asmooth consistency-stable grease, of a petroleum sulphonic acid soap,and

mineral oil.

'7. A grease as described in claim 6 in which the mixed soap of thefatty material is the sodalime soap of stearic acid and thesulfonic'acid.

. 0 an alkali metal soap of a saturated fatty ma- 2 rial and an alkalimetal-alkaline earth mixed soap of a fatty saturated material, the majorproportion of which is the alkali 'metal soap, from about 0.25% to about5.0% of a preferentially oilsoluble soap of a sulfonic acid or the typederived from petroleum oil, from about. 0.01% to about.

' 2.0% of an oxidation inhibitor and a mineral oil.

- the type suitable for ball bearing grease comprisdrocarbon.

11. A grease as described in claim 9 in which the oxidation inhibitor isthe neutralized reaction product of a phosphorus sulfide and an olefinpoly mer.

12. A grease as described in claim 9 in which the oxidation inhibitor isthe neutralized reaction product of phosphorus pentasulfide and an iso-13. A grease as described in claim'9 in which the oxidation inhibitor isa polyamine.

14, A grease as described in claim 9 in which the oxidation inhibitor istriethylene tetramine.

15. The method of preparing a low soap-content grease having a lowpenetration difi'erential, a smooth structure, resistance to oil leakageat elevated temperatures and stable against oxidation,

comprising mixing a saturated fatty material, an oil soluble soap ofsulfonic acid of the type derived from petroleum oil and sufllcientmineral oilto make a base containing from about 40% to about oil andfrom about 50% to about soap, heating the mixture to a temperature ofabout 225 F. to 235 F., adding a saponifying agent selected from thegroup consisting of an alkali metal basic compound and a mixture of analkali metal basic compound and an alkaline earth basic compound, themajor quantity of which is the alkali metal basic compound, in an amountsufficient to react with all of the fatty material and leaveapproximately 1% excess alkaline material in the base, maintaining thetemperature atabout 225 F. to 240 F. until the base becomes heavy andgradually increasing the temperature to about 280 -F. to about 300 F.and maintaining the mix ture at said last mentioned temperature untilthe base becomes short, heavy and plastic, grading in a mineral oil inan amount suflicient to reduce the soap content of the grease to notless than about 16. Tire method of preparing a low soap contentsoda-lime soap grease comprising mixing together stearic acid, sodamahogany soap and sufficient oil I to make a soap base containing fromabout 40% to about 50% mineral oil and from about 50 to about 60 soap,heating the mixture to atemperature of from about 225 F. to about 235F., adding the required amount of hydrated lime to the mixture to reactwith the stearic acid. gradually adding a 48 Baum solution of causticsoda to the mixture in an amountsufllcient'to react with all of theremaining stearic acid and leave approximately 1% excess caustic soda inthe base, maintaining the temperature at about 225 grease to notlessthan about 2% and not more than about 25% to the mixture andgradually reducing the temperature toabout 250 F. at which temperaturethe remainder of the oil is graded in,

rapidly cooling the graded mixture and stirrin the cooled mixture untilthe same is worked smooth.

17. The method of preparing a low soap-content grease comprising mixingtogether a saturated fatty material, an oil soluble soap of sulfonicacid of the type derived from petroleum oil and sumcient mineral oil tomake a base containing from about 40% to about 50% oil and from about50% to about 60% soap, heating the mixture to a temperature of about 225F.-235 F., adding caustic soda in a 48 Baum solution, in an amountsufllcient to react with all of the fatty material and leaveapproximately 1% excess alkaline material in the base, maintaining thetemperature at about 225 F. to 240 F. until the base becomes heavy andgradually increasing the temperature to about 280 F.-300 F. andmaintaining the mixture at said temperature until the base becomesshort,; heavy and plastic, gradually lowering the temperature to about160 F. while grading in the oil in an amount sumcient to reduce the soapcontent of the grease to not less than about 2% and not more than about25% required to obtain the desired consistency and filling said greasewhile at said last mentioned temperature.

- HUBERT J. LIEHE.

